Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.24.3 (collagenase)
 18,340 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

To obtain information about the evolution of acetylcholinesterase (AChE), we undertook a study of the enzyme from the skeletal muscle of the lamprey Petromyzon marinus, a primitive vertebrate. We found that the cholinesterase activity of lamprey muscle is due to AChE, not pseudocholinesterase; the enzyme was inhibited by 1,5-bis(4-allyldimethylammonium phenyl) pentane-3-one (BW284C51), but not by tetramonoisopropyl pyrophosphortetramide (iso-OMPA) or ethopropazine. Also, the enzyme had a high affinity for acetylthiocholine and was inhibited by high concentrations of substrate. A large fraction of the AChE was found to be glycoprotein, since it was precipitated by concanavalin A-agarose. Optimal extraction of AChE was obtained in a high-salt detergent-containing buffer; fractional amounts of enzyme were extracted in buffers lacking salt and/or detergent. These data suggest that globular and asymmetric forms of AChE are present. On sucrose gradients, enzyme that was extracted in high-salt detergent-containing buffer sedimented as a broad peak of activity corresponding to G4; additionally, there was usually a peak corresponding to A12. Sequential extraction of AChE in conjunction with velocity sedimentation resolved minor forms of AChE and revealed that the G1, G2, G4, A4, A8, and A12 forms of AChE could be obtained from the muscle. The identity of the forms was confirmed through high-salt precipitation and collagenase digestion. The asymmetric forms of AChE were precipitated in low ionic strength buffer, and their sedimentation coefficients were shifted to higher values by collagenase digestion.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Acetylcholinesterase from the skeletal muscle of the lamprey Petromyzon marinus exists in globular and asymmetric forms. 288 57

Rat obturator nerve 16S acetylcholinesterase (16S AChE) was separated by sucrose gradient velocity sedimentation and compared to the 16S form of AChE similarly derived from endplate regions of anterior gracilis muscles. The 16S AChE from both tissues could only be extracted in high ionic strength buffer; as it aggregated under low ionic strength conditions. Treatment of nerve and muscle 16S AChE with purified collagenase, in the presence of calcium, caused an identical "shift" in the enzyme's sedimentation coefficient to 17.5S. Other properties which were also equivalent for 16S AChE from both tissue sources included: an excess substrate inhibition above 2 x 10(-3) M acetylcholine and Km of 1.6 x 10(-4) M, relative sensitivity to the specific inhibitors BW284C51 (I50 of 5 x 10(-8) M) and Iso-OMPA (I50 of 5 x 10(-4) M), and a half maximal thermal inactivation at 62.5 degrees C. These and additional results indicate that the 16S forms of AChE in both tissues are analogous molecules, which have a highly asymmetric conformation probably containing a collagen-like domain. The present findings are also consistent with the view that motor neurons provide at least a fraction of the 16S AChE present at the neuromuscular junction.
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PMID:Properties of 16S acetylcholinesterase from rat motor nerve skeletal muscle. 732 60